diff mbox series

[LEDE-DEV] ar71xx: fix invalid pointer dereference in c60_nand_scan_fixup()

Message ID 20171213193150.2012-1-juhosg@freemail.hu
State Accepted
Delegated to: John Crispin
Headers show
Series [LEDE-DEV] ar71xx: fix invalid pointer dereference in c60_nand_scan_fixup() | expand

Commit Message

Gabor Juhos Dec. 13, 2017, 7:31 p.m. UTC 
Since Linux 4.6, mtd->priv no longer points to the NAND specific
structure. Under 4.9 it contains NULL, thus using it to access
the fields of the nand_chip structure causes an invalid pointer
dereference.

Update the code to use the mtd_to_nand() helper under 4.9 to obtain
the address of the chip specific data.

Compile tested only.

Fixes: 7bbf4117c6fe ("ar71xx: Add kernel 4.9 support")
Signed-off-by: Gabor Juhos <juhosg@freemail.hu>
---
 target/linux/ar71xx/files/arch/mips/ath79/mach-c60.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Christian Lamparter Dec. 14, 2017, 4:09 p.m. UTC | #1 
On Wednesday, December 13, 2017 8:31:50 PM CET Gabor Juhos wrote:
> Since Linux 4.6, mtd->priv no longer points to the NAND specific
> structure. Under 4.9 it contains NULL, thus using it to access
> the fields of the nand_chip structure causes an invalid pointer
> dereference.
> 
> Update the code to use the mtd_to_nand() helper under 4.9 to obtain
> the address of the chip specific data.
> 
> Compile tested only.
> 
> Fixes: 7bbf4117c6fe ("ar71xx: Add kernel 4.9 support")
> Signed-off-by: Gabor Juhos <juhosg@freemail.hu>
Tested-by: Christian Lamparter <chunkeey@gmail.com>

Yep, it boots on my unit.

Kernel is: Linux c-60 4.9.67 
"OpenWrt SNAPSHOT, r5518+1-bfa42ef8f5"


Thanks
Gabor Juhos Dec. 14, 2017, 8:27 p.m. UTC | #2 
Hi Christian,

2017.12.14. 17:07 keltezéssel, Christian Lamparter írta:
> On Wednesday, December 13, 2017 8:31:50 PM CET Gabor Juhos wrote:
> 
>> Since Linux 4.6, mtd->priv no longer points to the NAND specific
> 
>> structure. Under 4.9 it contains NULL, thus using it to access
> 
>> the fields of the nand_chip structure causes an invalid pointer
> 
>> dereference.
> 
>>
> 
>> Update the code to use the mtd_to_nand() helper under 4.9 to obtain
> 
>> the address of the chip specific data.
> 
>>
> 
>> Compile tested only.
> 
>>
> 
>> Fixes: 7bbf4117c6fe ("ar71xx: Add kernel 4.9 support")
> 
>> Signed-off-by: Gabor Juhos <juhosg@freemail.hu>
> 
> Tested-by: Christian Lamparter <chunkeey@gmail.com>
> 
>  
> 
> Yep, works on my C-60.

Great. Thanks for testing!

-Gabor

> 
>  
> 
> Kernel is: Linux c-60 4.9.67
> 
> "OpenWrt SNAPSHOT, r5518+1-bfa42ef8f5"
> 
> Thanks
>
diff mbox series

Patch

diff --git a/target/linux/ar71xx/files/arch/mips/ath79/mach-c60.c b/target/linux/ar71xx/files/arch/mips/ath79/mach-c60.c
index 7b01af515b..144f5db740 100644
--- a/target/linux/ar71xx/files/arch/mips/ath79/mach-c60.c
+++ b/target/linux/ar71xx/files/arch/mips/ath79/mach-c60.c
@@ -180,7 +180,11 @@  static const struct mtd_ooblayout_ops c60_nand_ecclayout_ops = {
 
 static int c60_nand_scan_fixup(struct mtd_info *mtd)
 {
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,6,0)
 	struct nand_chip *chip = mtd->priv;
+#else
+	struct nand_chip *chip = mtd_to_nand(mtd);
+#endif
 
 	chip->ecc.size = 512;
 	chip->ecc.strength = 4;